Mind and body in early modern philosophy

DOI: 10.4324/9780415249126-V043-1
Version: v1,  Published online: 2016
Retrieved December 12, 2018, from

1. Descartes

René Descartes argued that there is an incorporeal part of human beings, which is their mind or soul, and is what allows them to be rational and conscious. In his technical terminology, he believed that there is a ‘real distinction’ between mind and body. This means that a human’s mind and their body are two distinct substances and that either could possibly exist without the other – although, in fact, in living human beings, mind and body are always paired together. Moreover, mind and body are of two different kinds, having different principal attributes or essences. The essence of mind is thinking and all other features of a mind depend in some way on this. Typically, we might think of them as ways of thinking. The essence of body, meanwhile, is extension and all other features of body depend on this (see also Dualism).

Descartes argues for that view of the mind in the sixth of his 1641 Meditations on First Philosophy. The subtitle of the first edition of that work claimed that it demonstrated ‘the immortality of the soul’ (Descartes [1641] 1984: 1). The second edition moderated that claim, saying only that the work demonstrated ‘the distinction between the human soul and the body’ (Descartes [1641] 1984: 12). Still, we can see why Descartes might have thought that showing the mind to be really distinct from the body was a step towards showing it was immortal. A mind that is really distinct from body would presumably not be subject to processes of bodily decay. So, though the body may decompose after death, or be cremated, neither of these would affect an incorporeal being, such as Descartes thought he had shown the mind to be. Thus it is at least possible that the mind is immortal, and a significant obstacle to believing in any sort of human immortality is removed (see also Soul, nature and immortality of the).

The Sixth Meditation argument for the real distinction relies heavily on Descartes’s notion of clear and distinct perception or understanding. This sort of perception, Descartes believes, is undeniable – ‘so long as I believe something very clearly and distinctly I cannot but believe it to be true’ (Descartes [1641] 1984: 48) – and – because of the way God has created us and the rest of the world – gives us a reliable insight into things (see Epistemology, history of §4; Rationalism). In this argument, Descartes begins from the thought that everything I clearly and distinctly understand can be created by God. That is, it is in an important sense possible. Moreover, Descartes says, if I can clearly and distinctly understand two things, A and B, ‘apart from’ one another (Descartes [1641] 1984: 54), then I can be sure that God could create either without the other, and thus that they are really distinct, are two different substances (even if they both happen to exist and be connected in the actual world). But I also perceive facts about the nature of myself, or my mind – it is a thinking, unextended thing – and about the nature of body – that it is an extended thing. This, Descartes claims, shows that I can understand them apart from one another. Thus they are, given the previous claims, really distinct.

In his earlier Discourse on the Method (Descartes [1637] 1985), Descartes had offered a rather different set of reasons for his view of mind and body. These rely on empirical observation of the differences between human beings and non-human animals. The first difference involves language: though animals make noises, and indeed parrots can speak human words, non-human animals cannot, Descartes thinks, ‘show that they are thinking what they are saying’ (Descartes [1637] 1985: 140). Meanwhile, humans can use language. For Descartes this shows a sharp difference in kind between humans, who have reason, and all other animals, which lack it. Second, Descartes observes that animals do some things much better than us, but others much worse. A cheetah, for instance, can run faster than any human, but can make no start at all in many activities performed by humans. It cannot read philosophy books, or knit a scarf, or row a boat. Many humans do not do these particular things either: but very many humans could learn to do them, though no cheetahs could. Thus Descartes argues that animals, unlike human beings, are like specialized biological machines, designed and made to do one thing. Human beings, though, with their faculty of reason, can adapt themselves to many things (see also Animal language and thought). These arguments from the Discourse are not, directly, arguments for the real distinction argued for in the Meditations. They are, however, arguments that human beings have a unique mental ability, reason. Reason, Descartes thought, must belong to an incorporeal mind.

Citing this article:
Duncan, Stewart. Descartes. Mind and body in early modern philosophy, 2016, doi:10.4324/9780415249126-V043-1. Routledge Encyclopedia of Philosophy, Taylor and Francis,
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